I just started my first garden dedicated solely to butterflies last summer, so I'm looking forward to
the answers posted to your question.

I noticed the butterflies having a great time at my spring-blooming azaleas. I don't know the names of them, because they were here when I bought the house. The pink one got the most attention from the butterflies. They also like my Lamb's Ear and the wild clover in my yard.

I worked 3rd shift and my mind won't remember what other flowers I saw them nectaring on this spring. Maybe after I get some sleep I'll think of the rest.

Hi Mark! I am in zone 7a, so I am not the best person to answer your question, but I can tell you what has bloomed early in my yard. My Lilac bloomed and attracted early butterflies. The first flowers that I had to bloom were my Blanket Flower and my Strawberry Seduction Yarrow. My Butterfly bush pannicles are just now beginning to open. The first butterfly bushes to open here were Nanho Blue, Black Knight, and Royal Red. My Hyssop is also in bloom right now. Hope that helps a little.~`Angie

There aren't many plants that bloom REAL early in spring, Spaceman, but I've seen butterflies and hummingbirds hanging upside down on blueberry blossoms, so if you've got room for a blueberry bush, that might be used. And the fruit is a great bonus!
Native/wild azaleas bloom early. I've got LOTS of them in my woods, and I really enjoy walking the paths and watching the early butterflies and hummers nectaring on them.
I ordered a winter honeysuckle, a bush whose leaves look just like Lonicera sempervirens, our native coral honeysuckle. This one is supposed to bloom in the middle of winter, we'll see. It's in a container now, and I plan to plant it out whenever the roots have filled the pot, which may be soon. It's supposed to get big, so I'll be planting it on the edge of the woods somewhere, and I wanted it to be big enough to withstand possible deer browsing.
Other than than, early blooming roadside weeds are used.
Sherry

Butterflies were all over these plants when I was in southern Ohio during the first week of May a couple years ago. Last year, I planted some roots of it I got off the internet. Two came up, grew a few leaves and are dying back. Maybe they will do better next year.